问题描述
我有一个包含以下字段的架构:
Name of row | Type
--------------------------+--------
name | string
value1 | numeric
timestamp | bigint
这些行包含具有名称,数字值和bigint值的条目,这些值以纳秒为单位存储unix时间戳。使用TimescaleDB,我想使用time_buckets_gapfill
来检索数据。鉴于时间戳记存储在bigint中,因此非常麻烦。
我想获取以下时间间隔的汇总数据:5分钟,小时,天,周,月,季度,年。我设法使用普通的time_buckets
使其正常工作,但是现在我也想填补空白。我现在正在使用以下查询:
SELECT COALESCE(COUNT(*),0),COALESCE(SUM(value1),time_bucket_gapfill('5 min',date_trunc('quarter',to_timestamp(timestamp/1000000000)),to_timestamp(1599100000),to_timestamp(1599300000)) AS bucket
FROM playground
WHERE name = 'test' AND timestamp >= 1599100000000000000 AND timestamp <= 1599300000000000000
GROUP BY bucket
ORDER BY bucket ASC
这将正确返回值,但不会填充空白。如果我将查询修改为
time_bucket_gapfill('5 min',to_timestamp(timestamp/1000000000),to_timestamp(1599200000))
我会正确获得第一个条目,然后每5分钟清空一行。我该如何运作?谢谢!
Here是一个数据库小提琴,但由于不支持TimeScaleDB而无法正常工作。上面的查询返回以下内容:
coalesce | coalesce | avg_val
------------------------+-------------------------
3 | 300 | 2020-07-01 00:00:00+00
0 | 0 | 2020-09-03 02:25:00+00
0 | 0 | 2020-09-03 02:30:00+00
解决方法
您应该在time_bucket_gapfill中使用与表中的数据类型匹配的数据类型。以下查询将为您提供所需的信息:
SELECT
COALESCE(count(*),0),COALESCE(SUM(value1),time_bucket_gapfill(300E9::BIGINT,timestamp) AS bucket
FROM
t
WHERE
name = 'example'
AND timestamp >= 1599100000000000000
AND timestamp < 1599200000000000000
GROUP BY
bucket;
,
我已经设法根据Sven的答案来解决它。它首先使用他的函数来填补空白,然后将date_trunc称为消除多余的行。
WITH gapfill AS (
SELECT
COALESCE(count(*),0) as count,0) as sum,timestamp) as bucket
FROM
playground
WHERE
name = 'test'
AND timestamp >= 1599100000000000000
AND timestamp < 1599300000000000000
GROUP BY
bucket
)
SELECT
SUM(count),SUM(sum),date_trunc('quarter',to_timestamp(bucket/1000000000)) as truncated
FROM
gapfill
GROUP BY truncated
ORDER BY truncated ASC